What is the empirical formula of a compound containing 5.03 grams carbon, 0.42 grams hydrogen, and 44.5 grams chlorine?

C2H3Cl

C2H2Cl

CHCl4

CHCl3

The right choice is CHCl₃

Explanation:

To find the empirical formula firstly, change the mass to moles.

For Carbon:

no. of moles = (mass / molar mass) = (5.03 g / 12 g/mol) = 0.42 mol

For Hydrogen:

no. of moles = (mass / molar mass) = (0.42 g / 1 g/mol) = 0.42 mol

For Chlorine:

no. of moles = (mass / molar mass) = (44.5 g / 35.5 g/mol) = 1.25 mol

The ratio for Carbon and Hydrogen is 1 : 1

0.42 mol / 042 mol = 1.00

Then find a ratio between the moles.

The ratio of Chlorine to both Carbon and Hydrogen is 3:1

1.25 mol / 0.42 mol = 2.98 ≅ 3

So the ratio is 1 C : 1 H : 3 Cl.

So, the right choice is CHCl₃

Carbon usually forms four bonds one to Hydrogen and 3 to Chlorine atoms.

Chlorine usually forms one bond to Carbon atom.

Hydrogen usually forms one bond Carbon atom.